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LIBRARY OF CONGRESS, 

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UNITED STATES OF AMERICA. 



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THE FORMATION OF CONSTELLATIONS BY THE ANCIENTS 



THE PITH OF ASTRONOMY 

[ WITHO UT MA THEM A TICS] 

THE LATEST FACTS AND FIGURES AS DEVELOPED 
BY THE GIANT TELESCOPES 



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SAMUEL G. BAYNE 



WITH ILLUSTRATIONS 




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NEW YORK 

HARPER & BROTHERS PUBLISHERS 

1896 



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Copyright, 1896, by Harper & Brothers. 

All rights reaervtd. 



CONTENTS 



PAGE 

Introduction v 

The Solar System 1 

The Sun 7 

Mercury 17 

Venus . . 19 

The Earth 22 

The Moon 29 

Mars 35 

Jupiter .39 

Saturn 44 

Uranus . . . . • 49 

Neptune 52 

Comets 56 

Asteroids or Planetoids 65 

Shooting-stars . . . . . . . . . . 67 

The Fixed Stars 75 

The Constellations 93 

Nebulae 103 

Milky Way 106 

Double and Multiple Stars 109 

Interesting Items . 114 



ILLUSTRATIONS 



THE FORMATION OF CONSTELLATIONS BY 

THE ANCIENTS Frontispiece 

A RING THROWN FROM THE SUN FORMING 

A SEPARATE PLANET Facing page 2 

ORBITS AND COMPARATIVE SIZES OF THE 

PLANETS IN THE SOLAR SYSTEM ... 4 

A GREAT SOLAR SPOT AS SEEN BY LANG- 
LEY "• 8 

RELATIVE SIZES OF THE SUN AND PLANETS " 12 

THE RIM OF THE MOON, SHOWING MARE 

CRISIUM " 30 

OBSERVATIONS OF MARS SHOWING ITS 

CHANGES " 36 

THE PLANET JUPITER AND ITS BELTS . . " 40 

SATURN AND ITS RINGS 44 

THE COMET OF 1881, AS SEEN THROUGH 

PROFESSOR DRAPER'S TELESCOPE, JUNE 27 56 



VI ILLUSTRATIONS 

STRUCTURE OF A TEXAN AEROLITE. . . Facing page 66 

A SWARM OF METEORS MEETING THE EARTH " 68 

THE CONSTELLATIONS OF ORION, THE TWINS, 

AND THE BULL 76 

THE CONSTELLATIONS OF THE LION, THE 

HERDSMAN, AND THE GREAT BEAR . . 94 

THE GREAT NEBULA OF ANDROMEDA . . 102 

THE GREAT NEBULA ABOUT THE MULTIPLE 
STAR ORIONIS, IN THE CONSTELLATION 
OF ORION . 104 

THE CELEBRATED CRAB NEBULA NEAR 

TAURI " 106 

THE NEBULA IN THE MILKY WAY ... 108 

YERKES TELESCOPE " 114 



INTKODUCTION 

The large modern telescope, celestial 
photography, and improved astronomi- 
cal instruments have opened the field 
of astronomy to such an extent that 
the ideas, statements, and figures of a 
few years ago are no longer authentic. 
Happily for the credit of astronomers, 
the wonders of the skies have been un- 
derestimated, and those who thought 
that statements that had been pre- 
viously made regarding celestial won- 
ders were almost beyond credence will 
be pleased to find that they were not 
only true, but that in reality not more 
than half the truth had been told. 



Vlli INTRODUCTION 

The writer has had the temerity to 
compile this little book in a simple and 
concise form for the use of those who 
know but little or nothing of astronomy, 
with the hope that it may lead them 
further to investigate this most delight- 
ful science. No mention has been 
made of signs, Greek letters connected 
with the naming of stars, or the mathe- 
matical features usually given in larger 
works on this subject, as they would 
only tend to confuse those who are 
seeking for elementary knowledge and 
to learn at least something of the won- 
ders that surround us. When a lay 
reader has finished a large book on 
astronomy very little of the immense 
array of facts and figures can be re- 
tained in his memory. In this con- 
densed form it is to be hoped he can 
remember much that will be interesting 



INTRODUCTION IX 

and useful, should he go no further. 
It is also intended to furnish a ready 
reference for those who desire to re- 
fresh their memories on the points they 
have known but now forget, and to 
give that information in corrected form, 
from the most recent observations and 
calculations, without the loss of time 
incurred in searching larger works for 
simple information. For those who 
wish to recognize the constellations 
and celebrated fixed stars at sight — and 
what pleasure cap be greater than rec- 
ognizing them, as we do old friends, 
when they make their annual reap- 
pearance in the sky, if it be not that of 
pointing them out to acquaintances, 
who are usually eager to learn their 
identity and something of their his- 
tory ? — William Peck's Constellations, 
and How to Find Them, is perhaps the 



X INTRODUCTION 

best and easiest guide with which to 
find the stars ; it contains but a few 
pages of reading - matter and twelve 
maps, which clearly show where the 
stars are on any night in the year. 

The planets wander, as their name 
indicates, or rather they are changing 
their position to us at all times, and 
therefore cannot be located on a map, 
which if published would be incorrect 
in a month after its issue. However, 
the study of astronomy has of late 
years become so popular that most of 
the important newspapers employ as- 
tronomers to write articles on the ex- 
isting condition of the heavens, and 
those articles naturally describe the lo- 
cation of the planets then in sight, so 
that any intelligent inquirer may find 
them with comparative ease. It may 
further be stated that a powerful opera- 



INTRODUCTION xi 

glass will show many wonders that are 
lost to the naked eye, and that the 
largest telescope that can be mounted 
on a tripod and conveniently moved 
out of the owner's residence for observ- 
ing is a 3 J ■ inch lens ; a larger size 
than that needs a permanent founda- 
tion. It is an axiom in sight-seeing of 
all kinds that when fatigue commences 
instruction and pleasure end ; and this 
will be verified in using a small tele- 
scope that needs the support of the 
hands and arms : -it soon tires the ob- 
server. There is no satisfactory middle 
size between an opera - glass and a tele- 
scope mounted on a tripod. 

The figures given hereafter represent 
averages (where there is a difference of 
opinion) taken from the highest authori- 
ties, such as Sir William Herschel, Pro- 
fessor Young, of Princeton, Sir Robert 



xii INTRODUCTION 

Ball, Professor Langley, Camille Flam- 
marion, Professor Lockyer, W. H. War- 
ren, Garrett P. Serviss, and many others. 
The estimates, where it is practical, 
are given in round numbers, for the 
purpose of enabling the reader to re- 
member them. 

In beginning the order of chapters 
it will perhaps be best to commence at 
home, and our local solar system will 
be taken up first by a description of 
its members, starting with the centre, 
our sun, and running out to the fron- 
tier planet, Neptune, which is "one of 
the family," although it is more than 
two thousand seven hundred millions of 
miles from the earth. 



THE PITH OF ASTRONOMY 



THE SOLAR SYSTEM 

"That very law which moulds a tear, 
And bids it trickle from its source, 
That law preserves the earth a sphere, 
And guides the planets in their course." 

The natural division of the heavens 
most interesting to the inhabitants of 
the earth resolves itself into two great 
parts — namely, the solar system, consist- 
ing of the sun with the eight planets 
which revolve round it, and the great 
suns or fixed stars which shine in space 
at immense distances from the earth. 

The solar group and its planets in- 
terest us most because we live within 
its confines, and our earth is a part of 



2 THE PITH OF ASTRONOMY 

the system which enables ns to observe 
closely and easily determine the dimen- 
sions, distances, composition, color, and 
weight of our neighbors ; while the stars 
are so far from us that a large portion 
of our information regarding them is to 
some extent speculative. 

The sun is the centre of the solar 
system. Eight planets revolve around 
it — viz., Mercury, Venus, Earth, Mars, 
Jupiter, Saturn, Uranus, and Neptune, in 
the order named — and are held in their 
orbits by its powerful attraction. The 
sun is a fixed star, of a low magnitude 
as compared with the giants of space. 
The word planet means a wanderer, and 
these bodies appear to wander through 
the skies, changing their positions daily; 
while a fixed star does not move — per- 
ceptibly, at least — in a hundred years. 

The planets may be easily known 



to 
o 

H 

K 



to 
g 




THE SOLAR SYSTEM 3 

from stars by the fact that, with the 
exception of Uranus and Neptune (re- 
volving so far out in their orbits that 
they cannot be seen by the naked eye), 
they are larger to our sight than the 
stars, and shine with a steady flame, like 
a lamp, while the stars twinkle, as a 
bright point of light. Those who have 
telescopes may readily see the differ- 
ence ; a planet will show a distinct disk, 
while the most powerful instrument can 
only make the star point brighter and 
more brilliant. The cause of this is 
that the glass entirely fails to visibly 
magnify at such immense distances. 

The moon is a sort of grandchild, viz., 
a satellite of a satellite — that is to say, 
it revolves round the earth while the 
earth is revolving round the sun. And, 
for that part, there is yet another step 
to take in this direction, for undoubted- 



4 THE PITH OF ASTRONOMY 

ly the sun itself, with its entire system 
of followers, is attracted towards a 
giant sun, compared with which our 
little one is very small indeed. Most 
of the other planets have moons revolv- 
ing round them, which will be described 
in the proper place. It may be men- 
tioned here that the four planets near- 
est the sun — namely, Mercury, Venus, 
the earth, and Mars — are the smallest 
and densest, and each turns on its axis 
in about the same time, while the four 
outside giant planets — Jupiter, Saturn, 
Uranus, and Neptune — rotate in about 
ten hours, and are the planets of the 
least density. The first four are known 
as the " interior planets," and the latter 
are called the " exterior planets." 

An immense group of comets must 
be included in any description of the 
solar system, no matter how brief. 




ORBITS AND COMPARATIVE SIZES OF THE PLANETS IN 
THE SOLAR SYSTEM 



THE SOLAR SYSTEM 5 

These comets describe ellipses in their 
courses, and turn on the sun close to 
that orb, then run out into space, to 
return again in what is called their 
period — that is, the term of years that 
is consumed in completing their orbit. 
Some of them (notably Halley's comet) 
sail out far beyond Neptune, and as 
that would make a trip of six thousand 
millions of miles out and return, it is 
apparent that long intervals of time 
must take place between their appear- 
ances to us of the earth. In the vast 
distance between the orbits of Mars 
and Jupiter is found a great number 
of asteroids, as they are called. These 
also revolve round the sun, as do the 
larger planets, but they are so small by 
comparison that a more detailed de- 
scription of them will be deferred till 
later. 



6 THE PITH OF ASTEONOMY 

Allied closely to these, but still small- 
er, are the meteoric stones, which are 
scattered through the skies, and rush 
round the sun in shoals, from the size 
of a walnut to that of a house. All of 
these members are the component parts 
of our system, running in size from the 
giant planet Jupiter, almost 1300 times 
larger than our earth, down to stones 
not as large as oranges; yet all these 
bodies have orbits, composition, and 
speed differing from each other, but 
each holding its proper place in the 
solar system which we call our own. 



THE SUN 

The diameter of the sun is 866,000 
miles. 

Its mean distance from the earth is 
93,000,000 miles. 

Its volume, or bulk, is 1,300,000 times 
more than the earth. 

Its mean density is one-fourth that 
of our earth, or "about the consistency 
of a thick fluid. 

It revolves on its axis in about 25 
days. 

Its mass — that is, the quantity of 
matter in it — is more than 800 times 
greater than all the planets combined. 

The centre of gravity of the whole 



8 THE PITH OF ASTRONOMY 

solar system lies within the body of 
the sun when Jupiter and Saturn are 
not on one side of it. 

The force of gravity at the sun's 
surface is 28 times greater than the 
gravity on the earth. A man weigh- 
ing 217 pounds here would weigh 
over three tons on the sun, and his 
own weight would flatten and kill 
him. 

Light travels at the rate of 186,000 
miles per second, and reaches us from 
the sun in eight minutes. The light 
from the sun is 150 times as great as 
that of the lime cylinder of the calcium 
light, and it makes all other lights black, 
by comparison. With modern astro- 
nomical appliances the weight, size, and 
distance of the sun are now determined, 
and with the aid of the spectroscope 
scientists tell us the composition of the 




", '',iu; 



A GREAT SOLAR SPOT 

(As seen by Langley.) 



THE SUN 9 

sun, as well as of many of the fixed 
stars that surround us. 

The sun is believed to be a mass of 
intensely heated matter in the gaseous 
state, consisting of both the permanent 
gases, like hydrogen, and of metallic 
vapors powerfully compressed by its 
own gravity,* this compression causes 
it to contract, and the contraction, 
which amounts to ten inches daily, pro- 
duces the intense radiation that warms 
and supplies the solar system with en- 
ergy. If we take the sun's diameter 
into our reckoning, we find that it may 
require millions of years to perceptibly 
affect this vast globe and reduce its life- 
giving influence to a point where hu- 
manity will freeze to death ; but, after 
all, it is only a question of time, as the 
day will come when it will be reduced 
to a dark cinder, and travel through 



10 THE PITH OF ASTRONOMY 

space as dead and cold as the moon is to- 
day. It will then roam through the 
skies until perhaps it comes into colli- 
sion with another body, when both will 
turn into a nebula of floating gas, thus 
forming the nucleus of a new world, 
which may be a home for new men and 
new things. The sun, like all natural 
objects, must pass through the regular 
stages of birth, vigor, decay, and death. 

The heat radiated by the sun defies 
all human conception. It is a gigantic 
furnace, of such magnitude that com- 
parisons between it and what we know 
of heat are futile. 

A few of these may interest the read- 
er. If all the coal-fields on the earth 
w T ere ignited and consumed in a fire, 
they would not supply the heat emitted 
by the sun for the tenth part of a 
second. 



THE SUN 11 

If the earth were to fall into the sun 
it would melt and evaporate on arriving 
there, like a flake of snow. 

At the distance of 93,000,000 miles, 
were it not for the atmosphere that pro- 
tects the earth from the sun's rays, they 
would melt a crust of ice enveloping 
the earth 100 feet in depth in a year, 
and would cause all the oceans to boil 
in a like period. 

The sun's heat at its surface would 
also boil in an hour seven hundred thou- 
sand millions of cubic miles of water at 
the temperature of melting ice ; and yet 
more than 99 per cent, of all this heat is 
wasted, not having touched any of the 
planets on its way. Estimating the to- 
tal radiation of the sun at two thousand 
millions, the earth receives but one part 
of this. The noise of the terrific dis- 
turbance on the sun is of such power 



12 THE PITH OF ASTEONOMY 

that it alone would kill a man were he 
placed within 5000 miles from its rim. 
The sun has a continuous evolution of 
heat equivalent to 10,000 horse-power 
on every square foot of its surface. A 
procession of icebergs sent against the 
sun would be melted at the rate of 
300,000,000 cubic miles of solid ice per 
second. 

If it were possible to have started an 
express - train for the sun in 1635, it 
would not be due there till now, and a 
single ticket for the trip would have 
cost $3,000,000. If a small community 
had started on the train, the seventh 
generation only would reach its desti- 
nation. 

The ra} r s of heat from the sun on 
their way to the earth pass through a 
practical vacuum which has a tempera- 
ture of 300 or 400 degrees below zero ; 




RELATIVE SIZES OF THE SUN AND PLANETS 



THE SUN 13 

they pass through this temperature and 
have apparently no effect until they 
meet some object, like the earth, capa- 
ble of being warmed by them. 

The sun has prodigious activity in its 
spots. These spots are sometimes 50,000 
miles in diameter, and it is by observ- 
ing them disappear and return to our 
sight by rotation that the time of the 
sun's rotation has been determined. 

In 1858 a spot of over 107 } 000 miles 
in diameter was clearly seen. These 
spots are enormous vents for the tem- 
pests of flame that sweep out of and 
down into the sun. 

An up rush and down rush at their 
sides have been measured at 20 miles a 
second; a side rush or whirl at 120 
miles a second. These tempests rage 
from days to months at a time, and as 
they cease the advancing sides of the 



14 THE PITH OF ASTRONOMY 

spots approach each other at the rate 
of 20,000 miles an hour ; they strike to- 
gether, and the rising spray of fire leaps 
thousands of miles into space ; it falls 
again into the incandescent surge, and 
rolls over the Himalayas of fire as the 
sea over the pebbles on its beach. If 
ships were built as large as the whole 
earth, in such gigantic tempests they 
would be tossed like corks in an ocean 
storm. 

The incandescent gases which are 
seen on the surface of the sun some- 
times rise as high as 250,000 miles ; 
they shoot out to these great distances 
often at the rate of several hundred 
miles per second. 

The sun is our very life-blood ; with- 
out it we could not live an instant. It 
directly supplies us with light, heat, 
and other forms of energy, and indirect^ 



THE SUN 15 

ly with food, clothing, and everything 
else we use. This provident w r orker 
has stored coal, petroleum, and natural 
gas for us in the past ages, thus giving 
us an inexhaustible reservoir of power 
and light. It furnishes us with wood, 
and lifts the waters to the hills, so that 
in their passage to the sea man may be 
enabled to harness them for his use in 
producing the necessaries of life. 

It is the constant alternation of evap- 
oration and condensation that keeps 
all the waters of the earth in a state of 
purity, making them fit for us to drink, 
and preventing the oceans from becom- 
ing stagnant. The salt breezes that 
sweep over the storm-tossed seas purify 
the air, and so on, ad infinitum. 

We journey through a frigid space, 
but we live, as it were, in a conservatory 
in the midst of perpetual winter. "We 



16 THE PITH OF ASTRONOMY 

are roofed over by the air that treas- 
ures the heat, and floored beneath by a 
stratum both absorptive and retentive 
of heat — so that between the earth and 
air our vegetation and crops grow and 
ripen. 

We owe these obligations and many 
more to the sun ; it is little wonder, 
then, that men have bowed down and 
worshipped it in all ages. 



MERCURY 

The planet Mercury is 36,000,000 
miles from the sun. 

Its diameter is 3000 miles. 

Its year is 88 days. 

It moves in its orbit at a speed of 29 
miles per second. 

Its day is supposed to be 24 hours 
and 5 minutes. 

Mercury is the* nearest planet to the 
sun. It can never be seen by the naked 
eye except in the west a short time 
after sunset, and in the east a little be- 
fore sunrise. To see it, all the con- 
ditions must be favorable; it is said 
that the celebrated astronomer Coperni- 
cus never had the good fortune to see it. 



18 THE PITH OF ASTRONOMY 

It is usually lost in the glare of the 
sun, owing to its close proximity, and 
consequently the difficulty of observ- 
ing it is great. Astronomers have not 
agreed on the length of its days or the 
density of its atmosphere. 

Mercury is the densest member of 
the solar system. 

Mercury has no moon. 

When Mercury comes between the 
earth and sun, near the line where the 
plane of their orbits cut each other by 
reason of their inclination, the dark 
body of Mercury is seen on the bright 
surface of the sun. This is called a 
transit, and it occupies several hours in 
its completion, depending on the cir- 
cumstances of the transit. 

The next transit seen in this country 
will occur November 4, 1901. 



VENUS 

Venus is 67,000,000 miles from the 
sun, and is the second planet from it. 

Its diameter is 7700 miles. 

Its year is 225 daj 7 s. 

Its orbital speed is 22 miles per sec- 
ond. 

Its day is supposed to be a little over 
23 hours. 

It is sometimes called the evening 
star, and, as we see it, is the most mag- 
nificent planet in the solar system, ex- 
ceeding in light and beauty the bright- 
est stars ; its light is so vivid that it 
casts a perceptible shadow, and we some- 
times see it in full daylight. 



20 THE PITH OF ASTKONOMY 

The orbit of Venus is almost a per- 
fect circle; the paths of all the other 
planets are more elliptical. 

Venus has an atmosphere. It has no 
moon. Authorities do not agree on the 
length of the day on Venus, owing to 
the difficulty of observing the surface 
of the planet through its thick atmos- 
phere. 

An astronomical observation was 
made of Venus in Babylon in 685 b.c. 
It is written on a brick, which is now in 
the British Museum. 

The heat on Venus is much greater 
than on our earth. Its water is sup- 
posed to be in the form of dry steam, 
the dense atmosphere causing the re- 
tention of its heat. 

The dimensions of Venus make it a 
veritable twin of our earth, and in many 
other respects they resemble each other. 



VENUS 21 

Land and water are believed to exist, 



and some of the appearances suggest 
the existence of mountains 27 miles 
high. 
Venus is the ideal vision of the skies. 



THE EARTH 

" The globe terrestrial, with its slanting poles, 
And all its pond'rous load, unwearied rolls. " 

The earth is 93,000,000 miles from 
the sun, and is the third planet from it. 

The diameter of the earth is 8000 
miles. (Tg be exact, 7926 miles through 
the equator.) 

It revolves round the sun in 365 days, 
6 hours, 9 minutes, and 9 seconds. 

Its circumference is a little less than 
25,000 miles. 

It turns on its axis in 23 hours, 56 
minutes, and 4 seconds. 

The earth is some 3,000,000 miles 
nearer the sun in winter than it is in 



THE EARTH 23 

summer; consequently, the sun looks 
larger to our eyes at that time, but the 
solar rays strike the earth in our hemi- 
sphere more obliquely in winter and do 
not produce so much heat. 

The earth is as dense or heavy as it 
would be if composed entirely of metal- 
lic iron ore, which is five times heavier 
than water. 

Geologists tell us that it is hundreds 
of millions of years since the earth was 
in the condition of a molten mass of 
matter, with its crust just commencing 
to form as it slowly cooled. 

The earth is more rigid than glass, 
therefore probably no large proportion 
of its interior can be liquid, as many 
have supposed it to be. Its interior 
must be largely metallic. 

It is estimated that the earth is in- 
habited by fifteen hundred millions of 



24 THE PITH OF ASTRONOMY 

people. Its surface contains 187,000,000 
square miles, three-quarters of which 
are water. 

It may be estimated that something 
like four hundred thousand millions of 
men and women have lived since the 
advent of mankind. 

This globe has eleven known mo- 
tions. Among the most easily under- 
stood is its daily rotation on its axis, 
the passage over its orbit round the 
sun, and the motion towards the bright 
star Vega, towards which the entire 
solar system is flying. 

Viewed from Venus and Mercury, 
the earth is the brightest star of the 
firmament, lit up by reflection from the 
sun. 

The earth is flattened at the poles 27 
miles, and this leads to the truthful but 
paradoxical statement that the Missis- 



THE EARTH 25 

sippi Eiver runs up hill, as its mouth is 
three miles farther from the centre of 
the earth than its source. 

We fly through space at the rate of 
more than 18 miles a second, seventy- 
five times faster than a cannon-ball, 
and pass over our orbit round the sun 
in a year, the orbit containing 585,- 
000,000 miles. We thus travel 1,500,- 
000 miles daily through the skies, but 
never over the same path, as we are 
chained to the sun and follow its or- 
bit. 

We would be blown from the earth 
like dust did we not share its momen- 
tum, or if the envelope of air did not 
proceed with us. 

Were the earth suddenly arrested in 
its flight, or if it came into collision 
with another large body, the heat pro- 
duced would be so tremendous that 



26 THE PITH OF ASTRONOMY 

the entire globe would be instantly 
turned into gas and form a floating 
nebula. 

A soap-bubble in the wind could 
hardly be more flexible and sensitive 
to influence than the earth. If the 
water became more dense, or if the 
globe were to revolve faster, the oceans 
would rush to the equator, burying the 
tallest mountains and leaving the polar 
regions bare. If the water should be- 
come lighter, or the earth rotate more 
slowly, the poles would be submerged 
and the bottom of the equatorial oceans 
become an arid waste. No balance 
turning to the 1000th of a grain is 
more delicate than the poise of forces 
on this globe. Laplace has given 
us indisputable proof that the period 
of the earth's axial rotation has not 
changed the 100th part of a second 



THE EARTH 27 

of time in 2000 years. Man cannot 
make a clock that will tell the hours for 
a single day with the exactness that 
this vast globe has done for all recorded 
time. 

Sunrise greets a new 1000 miles at 
every hour; the glories of the sunset 
follow over an equal space some 12,000 
miles behind. While the east and west 
are gorgeous with sunrise and sunset, 
the north and south are often more re- 
markable still with their aurora bore- 
alis and Magellanic clouds. 

We in this latitude know but little 
of the glorious "Northern dawn. 55 It 
prevails near the arctic circle, and 
there takes many forms — cloud -like, 
arched, straight. It streams like ban- 
ners, w T aves like curtains in the wind; 
it is inconstant, and is either the cause 
or result of electric currents ; it is often 



28 THE PITH OF ASTKONOMY 

far above our atmosphere, sometimes as 
high as 600 miles. 

The realm of this royal splendor is 
yet an unconquered world, waiting for 
its Alexander. 



THE MOON 

"As when the Moon, refulgent lamp of night, 
O'er heaven's clear azure spreads her sacred 

light, 
Around her throne the vivid planets roll, 
And stars unnumbered gild the glowing pole." 

The moon revolves round the earth 
at a mean distance of nearly 239,000 
miles. 

Its diameter is 2160 miles. 

The volume or bulk of the earth is 
almost fifty times greater than that of 
the moon, and it would take 60,000,000 
of moons to equal the sun. 

The surface of the moon contains 
about the same number of square miles 



30 THE PITH OF ASTRONOMY 

that are found in North and South 
America. 

It completes its revolution round the 
earth in 27 days, 7 hours, 43 minutes, 
and 11 seconds, which is its sidere- 
al month ; the ordinary month, from 
new moon to new moon again, is 29 
days, 12 hours, 44 minutes, and 2 sec- 
onds. 

It revolves on its axis exactly in a 
sidereal month, and therefore always 
presents almost the same face to the 
earth; thus we never have seen the 
far side of the moon, nor will we ever 
see it. This circumstance causes the 
moon to have the longest day (caused 
by the sun's light) of any known celes- 
tial body — there are but twelve of them 
in our year. 

The moon travels round the earth in 
its orbit at a speed of 37 miles a minute, 




THE RIM OF THE MOON. SHOWING MAKE CKISIUM 



THE MOON 31 

and its orbit contains about 1,500,000 
miles. 

The moon varies in size to the eye, as 
the distance from us varies to the ex- 
tent of 25,000 miles in the course of a 
month. 

When the moon is between us and 
the sun that side which faces us is not 
lit up by reflected light, and we do not 
see it; when it forms a right angle 
with the sun we see half of its face, and 
when we are between it and the sun 
we see it as the full moon. 

A man weighing 155 pounds here 
would weigh but 26 pounds on the 
moon, and could, consequently, jump in- 
credible distances. 

The dimensions of the moon as com- 
pared with those of the earth are far 
greater than those of any other satel- 
lite in proportion to its primary. 



32 THE PITH OF ASTRONOMY 

The moon's day (caused by the sun's 
light) is almost thirty times as long as 
ours, and consists of fifteen days of day- 
light and fifteen days of darkness. 

As it has no atmosphere to protect 
it from the sun's rays its heat in day- 
light is intense — strong enough to boil 
water — while at night the cold is fright- 
ful, being several hundred degrees be- 
low zero. Lord Rosse estimates the 
difference between day and night to be 
500 degrees. 

The moon is a dead cinder ; if it ever 
had air and water, which it probably 
had, they are now absorbed in the 
porous lava that covers its surface. 

In consequence of the small gravity 
at the moon, the absence of the expan- 
sive power of ice and the levelling influ- 
ence of rains, precipices stand, moun- 
tains shoot up like needles, and cavities 



THE MOON 3a 

three miles deep remain unfilled ; these 
conditions give the moon grand and 
savage scenery, such as cannot be found 
on the earth. It has twenty-eight moun- 
tains higher than Mount Blanc ; ten of * 
these are over 18,000 feet high, the 
two highest, Mounts Leibnitz and Dor- 
fel, being almost 25,000 feet each. 

These mountains have been measured 
with greater accuracy than any of our 
own, and in a general w T ay the maps 
made of the moon are more reliable 
than those made of the earth. The ex- 
tinct volcanic craters on the moon are 
enormous. The crater of Clavius has a 
diameter of 130 miles. By the aid of 
powerful telescopes 33,000 craters have 
been counted on the side of the moon 
which we see. 

We are indebted to the moon for 
many things ; but the greatest of these 



34 THE PITH OF ASTEONOMY 

is that it is principally owing to its 
attraction that we have the purifying 
motion of the seas known as tides. 
"Without these daily currents the oceans 
would become stagnant and unhealthy 
to such an extent that we could not 
live on their shores. 



MARS 

The planet Mars is 141,000,000 miles 
from the sun. 

Its diameter is 4200 miles. 

Its years contains 687 days. 

Its mean distance from the earth is 
48,000,000 miles. 

The day on Mars is half an hour 
longer than ours, or about 24 hours and 
37 minutes. 

It has two moons. 

It moves at the rate of 15 miles a 
second. 

Mars is the fourth planet from the 
sun, and is called the red planet, from 
its well-known color. 



36 THE PITH OF ASTEONOMY 

The combination of its motion with 
ours causes it to pass behind us, or op- 
posite to the sun, once in two years. 
For two months at this period it is best 
seen, and appears as a red lamp in the 
sky ; at other times it looks small and 
unimportant. 

Its density and size are less than ours ; 
a man weighing 200 pounds here would 
weigh but 75 pounds on Mars. 

The orbit of this planet is decided- 
ly elliptical; it is 26,000,000 miles 
nearer the sun at the nearest part of 
its orbit than it is at the farthest, con- 
sequently the variation in heat from 
this cause alone is considerable. 

In many ways Mars resembles our 
earth : it has atmosphere, seasons, land, 
water, storms, clouds, and mountains ; 
it also snows and rains on Mars, as it 
does with us. Snow and ice cover 




OBSERVATIONS OF MARS SHOWING ITS CHANGES 



MARS 37 

both its poles, and produce great white 
patches at those points, which are clear- 
ly seen through a large telescope ; such 
an instrument also shows the markings 
on the land known as the canals. Fairly 
accurate maps have been made of Mars, 
showing its natural divisions of land 
and water to be about equal. 

It has been suggested that the vege- 
tation on Mars, for the most part at 
least, is yellow or orange, instead of 
green, as with us, thus giving the planet 
its color. 

It is but 3700 miles from the surface 
of Mars to its nearest moon, and that 
satellite revolves round it in seven 
hours and a half, showing all the 
phases of our moon in a night ; to an 
inhabitant of Mars it has the appear- 
ance of an enormous shooting - star 
slowly moving through the sky, and 



38 THE PITH OF ASTRONOMY 

would take our breath away if we saw 
anything- like it from our earth. 

Percival Lowell, of Boston, has late- 
ly devoted his life and fortune to the 
observation of Mars. He has erected 
an extensive observatory at Flagstaff, 
Arizona, and has been using it for this 
purpose for two or three years. He is 
now providing a special telescope with 
a magnifying power of 2400 diame- 
ters, for the purpose of examining this 
planet. 

Mr. Lowell's extended observations 
lead him to believe that Mars is in- 
habited by a highly civilized race of 
beings, who are now carrying on great 
engineering works, including the famous 
canals, which have been the subject of 
so much speculation. 



JUPITER 

"More yet remote from day's all -cheering 

source, 
Vast Jupiter performs his constant course ; 
Five friendly moons, with borrowed lustre, 

rise, 
Bestow their beams benign, and light his 

skies." 

Jupiter is the -fifth planet from the 
sun, and revolves round it at a mean 
distance of 483,000,000 miles. 

Its year is almost twelve of ours— or 
exactly 11 years, 10 months, and 17 
days. 

Its diameter is 88,000 miles. 

Its volume is about 1300 times that 
of the earth. 



40 THE PITH OF ASTRONOMY 

It is 390,000,000 miles from us when 
both Jupiter and the earth are on the 
same side of the sun. 

The day on Jupiter is less than ten 
hours. 

It moves over its orbit at the rate of 
eight miles a second. 

Its light is so brilliant that it casts a 
shadow. 

A man weighing 200 pounds here 
would, if carried to Jupiter, turn the 
scales at 500 pounds. 

A web of cloth as long as from the 
earth to our moon would fall short of 
encircling this great planet. Jupiter 
is flattened at the poles and bulges at 
the equator, owing to the speed of its 
rotary motion, and if it rotated a little 
faster it could not keep itself together, 
but would burst, and be spread on the 
skies like a coat of paint. 




THE PLANET JUPITER AND ITS BELTS 



JUPITER 41 

Its days are so short, in consequence 
of the rapidity of its rotation, that its 
year contains 10,455 of them. 

As its axis is vertical, there are no 
seasons such as we have, the most of its 
surface remaining in eternal spring. 

The clouds in the thick atmosphere 
take the form of immense belts, on 
which spots appear, both of which can 
be plainly seen through a telescope; 
the atmosphere over the equator moves 
faster than the air north or south of it, 
producing the effect of a violent wind 
constantly blowing over its equatorial 
zone at a velocity of 250 miles an hour. 

Jupiter has five moons; three of 
them are much larger than our moon, 
and one is larger than Mercury, having 
a diameter of 3600 miles. The near- 
est is 112,000 miles from the planet, 
and the most distant is 1,189,000 miles 



42 THE PITH OF ASTEONOMY 

away; they travel over their orbits 
with varying speed, and, with their 
primary, are known as the Jovian sys- 
tem. It is very probable that these 
worlds are inhabited — more probable 
than that Jupiter has now any inhabi- 
tants — as they have atmospheres and 
some of the requirements for sustaining 
life. Jupiter seems to be a world in 
process of formation, cooling in prepa- 
ration for the race that may at some 
future time occupy it. It has been said 
that this planet represents to-morrow, 
the earth to-day, and our moon yester- 
day. 

The magnificence of the celestial 
spectacle presented by the Jovian sys- 
tem is beyond description, as seen by 
one standing on the nearest moon. 
Jupiter presents an immense luminous 
disk, more than 3000 times the size of 



JUPITER 43 

our moon, while the sight is diversified 
by the other four worlds flying round 
in their orbits, and all comparatively 
close to the observer. These moons have 
a variety of color ; two are blue, one is 
yellow, and one red. Jupiter spins like 
a top in the centre, the moons rush 
round it, and the whole procession 
sweeps through the skies at the rate of 
500 miles a minute. Yet the disclosure 
of all this power, skill, and stability is 
but entering the vestibule of astronomy. 



SATURN 

"One moon to us reflects its cheerful light, 
There, eight attendants brighten up the night; 
Here, the blue firmament bedecked with stars, 
There, overhead, a lucid arch appears." 

Saturn's mean distance from the sun 
is 883,000,000 miles. 

It is the sixth planet from the sun. 

Its diameter is 75,000 miles, and it is 
the largest planet excepting Jupiter. 

It is 790,000,000 miles from the 
earth. 

It revolves round the sun in 29 years 
and 5 months. 

Its volume is 697 times that of the 
earth.. 



SATURN 45 

Its day is 10 hours, 14 minutes, and 
24 seconds. 

It has 25,000 days in its year. 

Its orbital speed is 6 miles a second. 

Eight moons revolve round it ; no 
other solar planet has so many. In 
composition it is lighter than water, 
and it has a dense atmosphere. 

The poles are flattened one-tenth of 
its diameter, which is a larger propor- 
tion than on any of the other planets. 

On account of the velocity of its ro- 
tary motion, gravity varies greatly on 
the surface ; the centrifugal force at 
the equator antagonizes gravitation to 
such an extent that while a man would 
weigh less there than he does here, at 
Saturn's pole he would weigh more 
than on the earth. 

Our opportunities for seeing Saturn 
vary greatly. As the earth at one part 



46 THE PITH OF ASTRONOMY 

of its orbit presents its south pole to 
the sun, then its equator, then the north 
pole, so does Saturn ; and we, in the di- 
rection of the sun, see the south side of 
the rings inclined at an angle; next, 
the edge of the rings appears like a fine 
thread of light, and then the north side 
at a similar inclination. It occupies fif- 
teen years in making all these changes. 

Galileo, with the first telescope, dis- 
covered Saturn's ring in 1610. In 1612 
the thin edge was turned towards the 
earth, and with his imperfect glass he 
could not see it ; greatly discouraged, 
and believing he had been deceived, he 
exclaimed, " Is it possible some demon 
has mocked me ?" He would never 
look at the planet again, and died with- 
out knowing that he had discovered the 
ring. 

Saturn is surrounded by an enormous 



SATURN 47 

flat, luminous ring, which is one of the 
greatest wonders of the heavens, and 
when seen through a telescope it com- 
pares favorably with any celestial sight. 

This ring is about 175,000 miles in 
diameter, and the average estimate of 
its thickness is 75 miles. 

The composition of the ring has caused 
much speculation. Laplace demonstrat- 
ed that it cannot be solid and survive 
an hour ; Peirce showed it could not 
be fluid and continue ; other authori- 
ties proved the impossibility of its be- 
ing composed of gas; and finally Max- 
well showed it must be composed of 
clouds of satellites, some of them prob- 
ably not larger than an orange, but all of 
them too small to be seen individually, 
and too near together for the spaces to 
be discerned. This theory is now ac- 
cepted as correct. 



48 THE PITH OF ASTEONOMY 

The ring has three divisions ; the in- 
nermost ring is dusky and transparent ; 
in contact with it is the brightest ring, 
called ring B; then comes a gap, and 
then the outer ring, known as ring A. 
There are other divisions, but they are 
not permanent. 

If the scenery of Jupiter is magnifi- 
cent, that of Saturn is unique. Here 
we have a universe, a colossal system, a 
wreath of vast proportions turned to 
silver by the reflection from the sun, 
and eight moons revolving outside its 
limits — travelling like pearls strung on 
a silver thread. No one has ever seen 
Saturn come into the field of a large 
telescope for the first time without sa- 
luting the spectacle with exclamations 
of surprise and delight. Saturn is the 
wonder of the solar system. 



URANUS 

Uranus is the seventh planet from 
the sun, and comes fourth in the or- 
der of size. Its mean distance from 
the sun is seventeen hundred and sev- 
enty - eight millions of miles, and 
from the earth it is sixteen hundred 
and eighty -five millions of miles dis- 
tant. 

Owing to its great distance, astrono- 
mers have not been able to determine 
the length of its day, but it has been 
estimated at 11 hours. 

Its diameter is 31,000 miles. 

It takes 84 years to make its revolu- 
tion round the sun. 



50 THE PITH OF ASTEONOMY 

Its volume is 69 times that of the 
earth. 

It has an atmosphere. 

It speeds over its orbit at the rate of 
4 miles a second. 

There is a great surprise in store for 
the observers of this planet. It has 
four moons, and they revolve round it 
from east to west, differing in this re- 
spect from the other planets, whose 
satellites revolve from west to east, 
and in about the plane of their equa- 
tors, while the followers of Uranus re- 
volve in a plane nearly perpendicular 
to that in which the planet moves — L e., 
this system rolls like a carriage-wheel, 
while all the others spin like roulette- 
wheels, the motion of the former being 
backward. 

Uranus may be seen by the naked 
eye, under favorable circumstances, as 



URANUS 51 

a sea-green star of about the sixth 
magnitude. Up to the time when large 
telescopes were first used Uranus was 
mistaken for a fixed star by those who 
observed it. 

On the night of March 13, 1781, Sir 
William Herschel saw through his glass 
that it had a disk and moved slowly 
through the heavens; this celebrated 
discovery deposed Saturn as the fron- 
tier planet, a position it had held from 
the beginning. As w r e will see in the 
succeeding chapter, this led to another 
discovery, and Uranus had, in turn, to 
give way to Neptune as the sentinel of 
the solar system. 

Herschel called his discovery Georgi- 
urn Sidus, in honor of his king and pa- 
tron ; the people called it Herschel, but 
astronomers finally decided on its pres- 
ent classical name as the proper one. 



NEPTUNE 

"Who there inhabit must have other powers, 
Juices, and veins, and sense, and life than ours ; 
One moment's cold like theirs would pierce the 

bone, 
Freeze the heart's-blood, and turn us all to 

stone." 



This planet is the eighth from the 
sun, and is third in mass and volume. 

Its mean distance from the sun is 
two thousand eight hundred millions of 
miles, and from the earth two thou- 
sand seven hundred and seven millions. 

Its diameter is 37,000 miles. 

It revolves round the sun in 164 of 
our years. 



NEPTUNE 53 

It has an atmosphere. 

Neptune is attended by one moon, 
which moves round it in about six 
days, at a distance of 260,000 miles ; and 
it is remarkable that its motion is ret- 
rograde. 

The telescopes at present in use do 
not show Neptune to us clearly enough 
to determine its diurnal motion, so the 
length of its day is unknown. 

It has the longest orbit and the slow- 
est motion of any planet, and although 
it travels over its annual path of sev- 
enteen thousand millions of miles at 
the rate of 200 miles a minute, it may 
still be called the tortoise of the skies. 

Since its discovery it has not as yet 
completed a third of its first rotation 
round the sun, and as it will not finish its 
initial trip till the year 2010, no one at 
present alive will live to see that event. 



54 THE PITH OF ASTEONOMY 

Neptune is invisible to the naked 
eye; when seen through a telescope 
the light we see has travelled from the 
sun to it and returned to us by reflec- 
tion, a double trip of five thousand five 
hundred and seven millions of miles, in 
something over eight hours. It would 
take an express train over 10,000 years 
to accomplish this task. 

There is no object-lesson in the won- 
ders of light that we can grasp so easily 
as this ; it is the longest return of light 
that the heavens afford us. 

Neptune is our frontier planet, and was 
discovered simultaneously by Adams, 
of England, and Leverrier, of France, 
in the autumn of 1846. Both believed 
it to exist from observing that its 
neighbor, Uranus, was retarded in its 
orbit by the attraction of some great 
unseen world. Both of these men gave 



NEPTUNE 55 

their calculations to astronomers pos- 
sessing large telescopes, directing them 
where to look for the great unknown — 
and both were successful. 

This, the last great discovery in as- 
tronomy, was sensational in every way, 
and is a standing monument to the 
highest reasoning powers of the hu- 
man mind. Had it been discovered 
by a mere survey of the heavens, one 
of man's greatest achievements would 
never have seen the light of day. 



COMETS 

The word comet is derived from the 
Latin word coma, meaning hair. Com- 
ets are celestial bodies which move 
round the sun in greatly elongated or- 
bits, usually elliptical or parabolic. 

A comet usually consists of a brill- 
iant point surrounded by nebulous light, 
which extends backward in the form of 
a tail or train. The nucleus or head 
has an undetermined amount of solid- 
ity, but stars may be clearly seen 
through all comets. 

Of the physical condition of comets 
little is at present known. Professor 
Young, of Princeton, states that a comet 




THE COMET OF 1881, AS SEEN THROUGH PROFESSOR 
DRAPER'S TELESCOPE, JUNE 27 



COMETS 57 

is nothing but a " sand-bank "; that is, it 
is a swarm of solid particles of unknown 
size and widely separate, say pinheads 
several hundred feet apart, each particle 
carrying with it an envelope of gas, 
largely hydrocarbon, in which gas-light 
is produced, either by electrical dis- 
charges between the particles or by 
some other light, the evolving action 
due to the sun's influence. This hypoth- 
esis derives its chief plausibility from 
the modern discovery of the close rela- 
tionship betw r een meteors and comets. 

He also states that comets may hurt 
us in two ways, either by actually strik- 
ing the earth or by falling into the sun, 
and thus producing such an increase of 
solar heat as to burn us up. 

In regard to the possibility of a colli- 
sion with a comet, Professor Pickering, 
of Harvard, says that it must be admitted 



58 THE PITH OF ASTRONOMY 

that such an event is possible; if the 
earth lasts long enough such a thing is 
practically sure to happen , for there are 
several comets' orbits which pass nearer 
to the earth's orbit than the semidiam- 
eter of the comet's head, and at some 
time the earth and comet will certainly 
come together. Such encounters will, 
however, be rare. If we accept the esti- 
mate of Babinet, they will occur once 
in 15,000,000 years, in the long run. 

It is impossible to estimate, for want 
of sure knowledge of the state of aggre- 
gation of the matter composing a comet, 
when such a conflict will take place. 
If we accept the modern theory, and if 
this theory be true, everything depends 
on the size of the separate solid parti- 
cles which form the main part of the 
comet's mass. If they weigh tons, the 
bombardment would be very serious, 



COMETS 59 

but if, as seems more likely, the parti- 
cles are smaller than pinheads, the re- 
sult would be simply a grand meteoric 
shower. 

Comets may be classed under two 
heads: those that return in their pe- 
riod — i, e., in a stated number of years 
(the orbit of this variety is always in 
the form of an ellipse) — and those that 
travel in a parabola whose direction 
will cause them to run out into space 
and never return to the sun. These 
are named, respectively, periodic and 
parabolic comets. 

Comets are further divided into those 
whose orbits lie within the solar system, 
and consequently have a short period, 
returning within a few years, and those 
whose path and direction carry them 
far beyond our system, returning after 
the lapse of centuries. 



60 THE PITH OF ASTRONOMY 

They are still further divided into 
those that can be seen by the naked 
eye and those that can only be seen by 
the aid of a telescope; the latter are 
known as telescopic comets, and the 
majority belong to this class. 

It is estimated that 20,000 comets 
have passed within sight of the earth 
since the birth of Christ ; of these 800 
have been observed, but it is reasonable 
to suppose that there are thousands of 
millions of them moving in all direc- 
tions in infinite space. 

All comets that visit the solar sys- 
tem and turn on the sun are raised to 
incandescence from its heat when ap- 
proaching and passing it ; it therefore 
naturally follows that they become 
more brilliant when in its vicinity. 

The comets of 1680 and 1843 were 
perhaps the most sensational that have 



COMETS 61 

ever been seen by men ; they were nearly 
alike in splendor and dimensions. The 
latter, flying at the inconceivable speed 
of 340 miles a second, turned round the 
sun from half -past nine till half -past 
eleven on the morning of February 27, 
1843. This is the greatest velocity that 
has been definitely measured by astron- 
omers; turning the celestial stake-post 
gave them the desired opportunity. Its 
tail was straight, and measured 198,000,- 
000 miles, and it is one of the won- 
ders of this observation that the tail 
was always opposite to the sun, and 
seemed not to be broken off or scat- 
tered on the skies when making such 
an abrupt turn in two hours. Astron- 
omers have calculated that it will re- 
turn to us in the year 2219 ; we may 
promise for our descendants that it will 
have a memorable reception. 



62 THE PITH OF ASTEONOMY 

The comet of Donati, in 1858, was 
the most beautiful that has been ob- 
served ; it had a brilliant head, and car- 
ried with it a curved tail measuring 
55,000,000 miles. Its period is about 
2000 years. 

The comet of Pons has a period of 
71 years; it appeared in 1812 and re- 
turned to us in 1883, and is due again 
in 1954. 

Comets frequently have more than 
one tail. The comet of 1744 had six 
tails, which spread like a celestial fan 
over the sky. 

Biela's comet was discovered by him 
in 1827, and it returned regularly in its 
period of six and one-half years. On 
its visit in 1846 it split in two defined 
comets, each having a head, coma, and 
tail. The twin comets returned "on 
time" in 1852, but have never appeared 



COMETS 63 

since ; they have undoubtedly been lost, 
or captured by the attraction of some 
larger body, and will never again return 
to the sun. 

Halley's comet is doubtless the most 
celebrated of all. Since the year 12 
b. c. it has appeared on twenty-four oc- 
casions ; its historical visits were in the 
year 1066, when William the Conqueror 
landed in England, and again in 1456, 
after the capture of Constantinople by 
the Turks. 

On many of its visits the inhabitants 
of Europe w r ere terror-stricken at its 
appearance. 

It has a period of 76 years, and its 
orbit reaches out beyond the planet 
Neptune. Halley observed it on its vis- 
it in 1682, and, applying the principles 
of Sir Isaac Newton, he identified it as 
the comet of 1066 and 1456. Tracing it 



64 THE PITH OF ASTRONOMY 

back to 12 b. c, and fixing its period 
at 76 years, he staked his professional 
reputation that it would return in 1758 
(after his death), in the memorable lines : 
" Wherefore if it should return, accord- 
ing to my prediction, in the year 1758, 
impartial posterity will not refuse to 
acknowledge that it was discovered by 
an Englishman." It appeared on Christ- 
mas day, 1758, and Halley has since 
held a niche in the temple of fame. 

We no longer regard a comet as a 
sign of impending calamity. We now 
look on them as interesting and beauti- 
ful visitors, which come to please and 
instruct us, but never to threaten or 
destroy. 



ASTEROIDS OR PLANETOIDS 

Between the orbits of Mars and Ju- 
piter there is a space of nearly 400,000,- 
000 miles. Up to the year 1800 this 
belt was supposed to be vacant. On 
January 1, 1801, Piazzi, an Italian as- 
tronomer, discovered the minor planet 
Ceres. This was followed by an embar- 
rassment of riches, and to day more 
than 400 have been found. 

Ceres is the largest. Professor Bar- 
nard gives it a diameter of 600 miles. 

Vesta is the brightest, as it can be 
seen by the naked eye. Its diameter is 
about 250 miles. 

Some of the smaller asteroids run 



66 THE PITH OF ASTEONOMY 

down to 20 miles in diameter and even 
lower, some authorities stating that 
there are shoals of them no larger than 
rocks. 

These planets revolve round the sun 
(on an average) in less than five years. 



SHOOTING-STARS 

The universe swarms with meteoric 
stones. These bodies, although very 
small, are of course not stationary, 
but revolve round the sun — that is, 
those that come within the domain of 
the solar system. They are governed 
by the same laws as the other bodies, 
and are a part of our system — a part 
of the unity of the universe. They 
have their region of travel, and the sun 
chains them and the giant Jupiter by 
the same power and influence. 

When they come near enough to the 
earth they are " captured " by it, and 
rush into our atmosphere with such 



68 THE PITH OF ASTRONOMY 

velocity as to produce a degree of heat 
sufficient to vaporize them and turn 
them into meteoric dust. During this 
process of burning they appear to us as 
shooting stars. 

They usually become luminous about 
75 miles from the surface of the earth, 
and are entirely consumed by friction 
before they descend to regions where 
the atmosphere is dense. In rare in- 
stances they are so large that they are 
not entirely consumed, but fall on the 
earth as meteoric stones in a heated 
condition. Specimens of them may be 
seen at most of our museums. These 
stones encounter the earth by day as 
well as by night, and simultaneously on 
all parts of the globe. Professor New- 
comb has demonstrated that one hun- 
dred and fifty thousand millions of them 
annually fall on the earth. If they were 



SHOOTING-STARS 69 

not melted through friction, we would be 
subjected to a continuous bombardment, 
destructive alike to our lives and our 
property. 

Professor Peirce states that the heat 
which the earth receives directly from 
meteors is the same in amount which it / / 

receives from the sun by radiation, and 
that the sun receives five-sixths of its heat 
from meteors that fall on it, so that, after 
all, these little stones may play a more 
important part in our personal affairs 
than we give them credit for. 

The dust caused by the destruction 
of these stones is often seen on the arc- 
tic snows, and is found at the bottom of 
the oceans, where it is subjected to but 
little agitation, owing to the compara- 
tive calm prevailing there. The writer 
has seen it taken from the bottom of 
the Indian Ocean by lowering a hoi- 



70 THE PITH OF ASTKONOMY 

low socket partially filled with soft 
wax. 

There are two thick streams of these 
stones that are annually encountered by 
the earth while its orbit is crossing 
theirs. The first meeting is on the 
night of August 10th ; the second swarm 
is encountered on November 14th, at 
about three in the morning. The No- 
vember belt is thin, and the earth runs 
through it in a few hours. 

The August stream is more scattered, 
and we see these apparitions for some 
nights both before and after the 10th, 
which is the central date of their ap- 
pearance in the skies. 

There have been many remarkable 
star showers on these two dates — the 
most memorable in November, 1833 ; 
Olmsted, the astronomer, estimated that 
from the single point where these obser- 



SHOOTING-STARS 71 

vations were made 240,000 stars fell 
during the shower, which lasted seven 
hours. 

Stone showers and the fall of large 
stones have been more or less frequent 
in history. 

Several thousands of stones fell in 
Hungary on June 9, 1866, with fright- 
ful noise ; the largest fragment weighed 
646 pounds. 

The largest authentic aerolite is that 
found at Bendigo, Brazil, in 1816; it 
weighs five and- a half tons ; it was 
conveyed to Rio Janeiro in 1886. 

On the evening of December 21, 
1876, a meteor of unusual size and 
brilliancy passed over the states of 
Kansas, Missouri, Illinois, Indiana, and 
Ohio. It was first seen in the western 
part of Kansas, at an altitude of sixty 
miles. In crossing the State of Mis- 



72 THE PITH OF ASTRONOMY 

souri it commenced to explode, and this 
breaking up continued while passing 
over Illinois, Indiana, and Ohio, till it 
consisted of a large flock of brilliant 
balls chasing each other across the sky, 
the number being variously estimated 
at from 50 to 100 ; it was accompanied 
by terrific explosions, and was seen 
along a path of not less than 1000 miles. 
The writer's recollection of the occur- 
rence is that the stones were lost in 
Lake Erie. 

While writing these lines the news 
comes through the Continental papers 
that one of the greatest meteorites 
ever seen recently shot across Spain, 
coming into sight over the Atlantic, 
and falling into the Mediterranean, 
or perhaps reaching the desert of Sa- 
hara, in Africa. On the morning of 
February 10, 1896, this body passed 



SHOOTTNG-STAKS 73 

over Madrid with deafening explosions 
and a vivid glare of blinding light ; it 
appeared as if enveloped in a bluish 
white cloud bordered with red ; the 
city was shaken as with an earthquake, 
many windows were broken, and some 
light structures were levelled to the 
ground ; the barometer fell, and after- 
wards rose rapidly. Nearly all of Spain 
was treated to a pyrotechnic display; 
incandescent fragments fell from the 
flaming meteor at Logrono and set the 
town on fire in two places. 

There are many varieties of these 
bodies, differing in size, chemical com- 
position, color, and origin : such as the 
ruins of vanished worlds scattered into 
space, the debris of comets, the product 
of volcanoes on stars and planets, which 
may include bodies projected from erup- 
tions on our own earth in the violent vol- 



74 THE PITH OF ASTRONOMY 

canic disturbances that have undoubt- 
edly taken place upon it in prehistoric 
days ; in other words, they represent the 
accumulation of filings, fragments, and 
dust from the celestial workshop in 
the manufacture and disintegration of 
worlds. 



THE FIXED STARS 

We have finished our brief notice of 
the solar system and all that it con- 
tains which will interest the casual 
reader, and must therefore now cross 
the " Great Divide " to the infinite be- 
yond. 

What does crossing this divide mean ? 
It means that we must leap the abyss 
from Neptune, our solar outpost, to the 
nearest body in space, the fixed star 
Alpha Centauri, some twenty-five thou- 
sand billions of miles distant ; then an- 
other stride of nearly twenty-five thou- 
sand billions more, and we come to our 
second neighbor, the star 61 Cygni. 



76 THE PITH OF ASTRONOMY 

What has been said of our system 
will not more than represent the de- 
scription of a few grains of sand as 
compared with the gigantic machinery 
that is in active operation beyond the 
confines and influence of the sun. The 
fixed stars will claim our first atten- 
tion. 

All the stars we see in the heavens 
are popularly called "fixed stars," to 
distinguish them from the wandering 
planets of the solar system. The name 
was given them by the ancients, when 
they were believed to be stationary. 
Modern science has shown that none of 
them are " fixed," but that every one of 
them is flying through the universe in 
some direction, with a velocity that is 
simply incredible to those who have 
not studied the subject. 

The briefest reflection will satisfy any 



THE FIXED STARS 77 

intelligent mind that the laws of nature 
will not permit any body to hang sus- 
pended in space without motion ; it 
must move or fall in some direction, 
and when it falls it moves ; so, then, it 
clearly follows that all is motion in the 
heavens, and that nothing is "fixed" 
or stable. All we either see or know 
of fly, fall, roll, or rush through the void, 
and yet, seen as a whole, all seems re- 
pose. But it is not so. Each sun is 
moving with a fearful velocity. 

The equilibrium of the stars, like that 
of our planets, is maintained by the ex- 
act balance of centrifugal force and the 
attraction of gravitation ; were it not 
for the balance and harmony held by 
these forces all would soon be turned 
to chaos, and constant collision would 
destroy the worlds in existence. The 
velocity at which these bodies are mov- 



78 THE PITH OF ASTEONOMY 

ing is so great that, were they to meet, 
they and all they contain would be 
turned into vapor in less than a second 
of time. 

In order to facilitate the indication 
of the size and brightness of a star, all 
the stars have been classed in the order 
of their magnitude. The word magni- 
tude, however, is misleading, as it has 
no connection with the real size of a 
star, but simply indicates how they ap- 
pear to our eyes. Thousands of stars 
that we can hardly perceive are un- 
doubtedly giant suns; but, owing to 
their immense distance, they appear to 
us as mere specks on the firmament. 
This can be readily illustrated by look- 
ing at the moon and Jupiter in our 
little system ; the moon is but a mere 
fraction of Jupiter in reality, but, ow- 
ing to the difference in distance, Jupi- 



THE FIXED STARS 



79 



ter appears to us like a spark of light 
compared with the size of our satel- 
lite. 

Astronomers have agreed on 19 stars 
of the first magnitude ; of these, 6 are 
seen in the southern hemisphere, leav- 
ing us 13 to deal with. They are as fol- 
lows, in the order of their apparent 
size and brilliancy : 



Sirius, . 
Arcturus, 
Vega, . . 
Rigel, 
Gapella, . 
Procyon, 
Betelguese, 
Aldebaran, 
Antares, 
Alt air, . 
Spica, . 
Fomalhaut, 
Regulus, . 



Of the constellation 

of the Great Dog. 
of the Herdsman, 
of the Lyre, 
of Orion, 
of the Wagoner, 
of the Little Dog. 
of Orion, 
of the Bull, 
of the Scorpion, 
of the Eagle, 
of the Virgin, 
of Australis. 
of the Lion. 



80 THE PITH OF ASTRONOMY 

The line between the last of the above 
list and the first stars of the second mag- 
nitude is very thin; many would, for 
instance, include the second-magnitude 
stars Castor and Pollux within the lim- 
it of the first. We count 59 stars of the 
second magnitude and 128 of the third ; 
the stars in the succeeding magnitudes 
run into the thousands. 

Of all the stars there are but 23 
whose distance has been measured ; the 
others are so far away that no angle or 
parallax can be found for them even by 
observing them from the opposite sides 
of the earth's orbit, which in itself is 
about 200,000,000 miles in diameter. 

The last sun in this list that has been 
measured is the catalogue star, 1830 
Groombridge, having a distance of 
four hundred and twenty-six thousand 
billions of miles. Of the distance of all 



THE FIXED STARS 81 

the hosts of heaven, with the above ex- 
ceptions, we know nothing. 

Alpha Centauri is the nearest sun ; 
it is twenty-live thousand billions of 
miles from us. It would take an ex- 
press train 73,000,000 years to reach it 
from the earth. 

The next nearest star is 61 Cygni; 
it may be seen in the constellation of 
the Swan on any clear night; it is 
forty -nine thousand billions of miles 
from this planet. 

We know more than a million stars, 
separately observed, catalogued, and 
registered on celestial charts, but the 
large modern telescope can now reveal 
stars of the fifteenth magnitude, and 
this brings hosts of new suns to our 
knowledge, estimated to be at least 
100,000,000 in number. 

Celestial photography penetrates still 



82 THE PITH OF ASTKONOMY 

further and shows more, so that 20,000 
stars are now known to exist for every 
one we see with the naked eye. 

In the memory of man many stars 
have changed ; some have faded from 
view, others have become brighter, 
while a few have changed their color, 
notably Algol, the variable star ; it was 
formerly red, but is now white. 

All the stars are moving in one di- 
rection or another. It takes Arcturus 
800 years to move so small a distance 
as twice the apparent diameter of the 
moon, yet it is moving at the rate of 
sixteen hundred millions of miles year- 
ly ; its distance is so great it does not 
appear to move. Another example, 
Sirius, takes 1300 years, apparently, to 
move but a few inches in the sky, yet 
its minimum speed is about 2,000,000 
miles every day. 



t 



THE FIXED STARS 83 

It was not always safe to make such 
assertions, however, as Giordano Bruno 
was burned alive in Eome in a.d. 1600, 
by order of the Inquisition, for asserting 
that the earth was not standing still 
and was not the centre of the universe. 
Again in 1616 and 1633, Galileo, one of 
the greatest of astronomers, was im- 
prisoned for the same cause, the Pope 
ordering that all books should be de- 
stroyed that asserted the motion of the 
earth. 

Some stars are advancing to us, others 
receding at great velocity ; but their 
size and the distance is so enormous 
that these factors count but little in 
their appearance to our eyes. Some of 
the larger stars ftying towards us are : 
the Pole Star, at the rate of 46 miles a 
second ; Vega, at 44 ; Arcturus, at 50 ; 
and Pollux, at 40 miles ; while a few 



84 THE PITH OF ASTRONOMY 

of those receding are : a Coronse, at a 
speed of 48 miles a second ; Castor, at 28 ; 
Capella, at 27 ; Kegulus, at 23 ; and Sirius, 
the Dog Star, at 22 miles a second. 

It will thus be seen that while the 
twins Castor and Pollux have stood 
side by side in the heavens — at least, to 
human eyes — for 4000 years, yet they 
are flying apart at the velocity of 68 
miles a second, which in a day amounts 
to over 5,000,000 miles. This for 40 
centuries, and still they are " the twins " 
to our eyes to-day. 

The student of stars will in a short 
time begin to see that they have indi- 
vidual colors. Many of these are clear- 
ly marked, and the observer will at once 
notice their various tints. It is believed 
they take their colors from their chem- 
ical composition in a state of incandes- 
cence. 



THE FIXED STAES 85 

Aldebaran and Antares are red ; Be- 
telguese is orange; Sirius, Vega, and 
Altair are bluish white; Arcturus, 
Capella, and Pollux are yellow; while 
others have tints of the ruby> the emer- 
ald, the topaz, and the sapphire. 

There are many variable stars — that 
is, stars which grow bright and then 
fade in a fixed period. Of this class 
Mira and Algol are the most remark- 
able. Mira attains the size of a sec- 
ond-magnitude star and remains in 
that condition 15* days; then it grad- 
ually fades and remains invisible for 5 
months; afterwards it reappears and 
increases slowly, to again become brill- 
iant; the entire transformation occu- 
pies 331 days. Mira is sometimes called 
" the wonderful." 

One of the accepted explanations of 
these changes is that it alternately 



86 THE PITH OF ASTRONOMY 

burns fiercely and smoulders within the 
time of its period. 

Algol has a short, exact period of 2 
days, 20 hours, and 48 minutes, in which 
it makes the change from its brightest 
to its faintest condition. It has kept 
time to these figures for 300 years. 
These changes are caused by the eclipse 
of this sun by an enormous dark satel- 
lite. The ancients named Algol " the 
demon." 

The most astonishing change comes 
from the southern sky. In the constel- 
lation of Argo the star known as Eta, 
in 1843, disputed with Sirius the pre- 
miership of the skies. In 1856 it com- 
menced to decrease, and gradually be- 
came smaller, till at length, in 1870, it 
left our sight. Seen at present with a 
telescope it is reviving, and may in the 
coming century regain its lost glory. 



THE FIXED STARS 87 

If this sun has satellites and they are 
inhabited, all their living beings must 
have perished from loss of heat. 

In 1572 Tycho Brahe observed a new 
and bright star that suddenly appeared 
in the constellation of Cassiopeia. It 
was so bright it could be seen in day- 
light. It gradually faded from sight 
in 17 months, and has never been seen 
since. 

The causes of these momentous 
changes in the great suns of space are 
largely a matter of speculation. There 
is little if any doubt that there exists a 
great number of extinct, burnt-out suns 
— enormous black balls that gravitate 
round other dark bodies — constituting 
dead systems. The dying throes of 
these monsters may have taken place in 
a celestial conflagration ending in their 
total darkness. 



88 THE PITH OF ASTKONOMY 

Another theory lately advanced by 
Professor Lockyer is that there is the 
closest possible connection between neb- 
ulae and stars, and the first stage in 
the development of cosmical bodies is 
not a mass of hot gas, but a swarm of 
cold meteorites. Many bodies in space 
which look like stars are really centres 
of nebulae — that is, of meteoric swarms — 
and stars with bright line spectra must 
be associated with nebulae. Some of 
the heavenly bodies are increasing their 
temperatures ; others, on the contrary, 
are decreasing. Double swarms, in any 
stages of condensation, may give rise 
to the phenomena of variability. New 
stars are produced by the clash of me- 
teor swarms, and are closely related to 
nebulae and bright line stars. Cosmical 
space is a meteoric plenum. The sun is 
one of those stars the temperature of 



THE FIXED STARS 89 

which is rapidly decreasing, and many 
of its changing phenomena are due to 
the fall of meteoric matter upon the 
photosphere. 

In point of speed, the most remarka- 
ble star in the universe is the seventh- 
magnitude catalogue star, 1830, Groom- 
bridge ; it is invisible to the naked eye, 
but can be found with a glass, in the 
Great Bear. Its terrific speed is such 
that it has led astronomers to believe 
it is not propelled by any force we know 
of, but by some -power from another 
universe, and that it is simply a vis- 
itor passing through our skies. It is 
rushing on at a rate of 17,000,000 miles 
daily. 

61 Cygni comes next to it in velocity. 
This star may be seen with the naked 
eye in the constellation of the Swan ; 
its pace is over 100 miles a second. 



90 THE PITH OF ASTKONOMY 

The giants Arcturus, Vega, and Ca- 
pella also move at a high rate of speed. 

The light from the fixed stars is a 
long time in reaching the earth ; from 
the very nearest it is about four years 
in coming, and from the stars that are 
so faint that we can hardly see them 
it takes many thousands of years to 
reach us. Good authorities estimate it 
in some cases as long as 100,000 years. 
At the rate the stars are moving we, 
then, never really see them, as they are 
billions of miles away from the point 
when the light we see left them. It 
also follows that succeeding generations 
see stars that have become extinct for 
thousands of years. 

It is not the present state of the sky 
which is visible, but its past history. 

The earth, besides rotating on its axis 
and revolving round the sun, reels like 



THE FIXED STARS 91 

a mighty gyroscope, but with so slow a 
motion that it takes 26,000 years to 
make one complete revolution of its 
axis round an imaginary line perpen- 
dicular to the plane in which the earth 
moves. Still further : as this axis of the 
earth moves in its circuit round this 
perpendicular line it points successively 
to different parts of the heavens, and as 
the point in the heavens to which the axis 
is directed will not have any diurnal mo- 
tion, all the stars will appear to revolve 
round it, or round the star that may be 
nearest to it ; from which circumstance 
it will be called the Pole Star. 

Polaris, the present Pole Star, appears 
" fixed " at the axis of the earth, but in 
a few hundred years it will gradually 
commence to wear away from it, and 
in about the year 9000 our descendants 
will elect Alpha Cygni as their guide, 



92* THE PITH OF ASTKONOMY 

while 13,000 years from now it will be 
the beautiful first-magnitude star Vega 
that will review the heavenly host. 

Polaris has held the post of honor for 
over a thousand years, and was pre- 
ceded in office by Thuban, of the Drag- 
on, to see which in daylight the long 
tunnel in the Pyramid of Cheops was 
built. 

The writer visited an observatory in 
China in 1874 said to be 4000 years old, 
in which were originally placed two 
bronze eyeholes on a slanting granite 
wall for the purpose of sighting Thu- 
ban, the Pole Star of that era. In 1874 
the line of sight through these holes 
pointed to a void, all the stars having 
moved away from it. 



THE CONSTELLATIONS 

1 * Orion's beams ! Orion's beams ! 

His star-gemm'd belt, and shining blade, 
His iles of light, his silv'ry streams, 
And gloomy gulfs of mystic shade." 

From the very earliest ages the stars 
have been watched with interest and 
admiration, and their movements traced 
and applied to various useful purposes. 
In those days " the stars in their courses" 
ruled the fate of men and nations. 

For the purpose of identifying the 
stars and finding out more about them, 
the first watchers of the sky divided the 
heavens into groups or constellations, 
naturally naming each group after some 



94 THE PITH OF ASTRONOMY 

object to which they fancied it had a re- 
semblance. As the first observers were 
chiefly herdsmen, we can readily con- 
ceive how some of the oldest constella- 
tions have been called after objects and 
animals with which the shepherds would 
be familiar in those early times. 

Later in our history the Greeks set 
their mythological deities in the skies, 
and read the revolving pictures as a 
starry poem ; they colonized the earth 
widely, but the heavens completely, and 
nightly over them marched the grand 
procession of their apotheosized divini- 
ties. The heavens signify much inore 
to us, but we retain the old groupings 
and pictures for our convenience in find- 
ing individual stars. An acquaintance 
with the names, peculiarities, and move- 
ments of the stars at different seasons 
of the year is an unceasing source of 



s 
> 




THE CONSTELLATIONS 95 

pleasure ; one can never be alone if one 
is familiarly acquainted with the stars. 

The constellation that is known to 
almost every one — young and old — is 
the Great Bear, popularly known as 
the Dipper, or Plough. The reasons for 
this are that it is a circumpolar constel- 
lation — consequently it is always in 
sight, revolving close to the Pole Star 
— and that it has a remarkable appear- 
ance, which all can recognize. 

The two stars on the edge of the 
Dipper are near the Pole Star, and a 
line drawn through them points to it; 
they are, therefore, called the "point- 
ers." This constellation contains no 
stars of first magnitude. 

The group known as Cassiopeia, or 
Cassiopeia's Chair, is a companion to 
the Dipper, and is always opposite to it, 
as both swing round the pole. 



96 THE PITH OF ASTKONOMY 

The grandest constellation is the 
giant Orion. It contains seven brill- 
iant stars, two of them of the first 
magnitude — viz., Betelguese and Eigel. 
Three stars lie in an oblique line across 
the middle of this group, and are known 
as Orion's Belt. Flammarion calls this 
group the California of the sky, be- 
cause it not only contains the above 
treasures, but in the middle of the belt ^o 
is found the wonderful nebula; viewed 
through a powerful telescope there are 
but few celestial sights that cope with 
it in weird grandeur. 

Canis Major, or the Great Dog, ad- 
joins Orion, and is remarkable because 
it contains Sirius, or the Dog Star — 
the monarch of the skies and the great- 
est of them all in brilliancy and size. 

Bootes, the Herdsman, contains the 
giant flying sun Arcturus, which looks 



THE CONSTELLATIONS 97 

so large that it may be mistaken for 
a planet. This star was recorded by 
Job and exploited by Homer. It is 
approaching us at a speed of 50 miles 
a second. 

Ursa Minor, or the Little Bear, is 
interesting only because in it is placed 
Polaris, known also as the Pole Star 
or North Star. It is the guide of the 
sailor at sea, and has been used by the 
slave to point his way to freedom. It 
apparently never moves, or at least so 
little that its mot-ion need not be dis- 
cussed here. 

Taurus, the Bull, claims attention be- 
cause it contains a celebrated group, 
the Pleiades, mentioned by Job, and the 
theme of poets since writing began. 
The ordinary observer can see six stars 
in this group; many can make out 
seven ; but Dawes, the keen - sighted 



98 THE PITH OF ASTRONOMY 

Englishman, counted thirteen under fa- 
vorable circumstances. A recent pho- 
tograph taken in Paris shows over 2000 
in it. Aldebaran, the great red sun, is 
the eye of the bull, and may be easily 
located on account of its marked color. 
The constellation of the Lyre is not- 
ed because of Vega, the most beautiful 
and one of the largest stars in the sky. 
It may be recognized by the formation 
of a small equilateral triangle with two 
minor stars. By the latest decisions 
of astronomers the solar system is fly- 
ing towards this point. Vega can al- 
ways be seen on a clear night, but is 
more brilliant when overhead in winter. 
This is true of all stars and planets; 
when they are on the horizon we have 
to look through so much more atmos- 
phere that they become dim to our 
sight. 



THE CONSTELLATIONS 99 

Leo, the Lion, may be known by the 
exact resemblance it now bears to a 
sickle. It contains Regulus, or the 
Lion's Heart, as well as Denebola. It 
is also a sign of the zodiac. 

Aquila, the Eagle, contains the brill- 
iant white star Altair, having small 
companions close to it on each side, 
the three making a straight line. 

Cygnus, the Swan, may always be 
found in the Milky Way ; it resembles 
a large cross or the skeleton of a kite 
more than it does u swan. 

The other celebrated constellations 
containing first - magnitude stars are 
Auriga, the Wagoner, containing Ca- 
pella, a brilliant yellow star ; the Little 
Dog, with Procyon within its limits ; 
the Scorpion, with the red star Antares ; 
the Virgin, containing the brilliant sun 
Spica as its feature. There are about a 



100 THE PITH OF ASTRONOMY 

hundred other constellations, but they 
have little interest for those not mak- 
ing them a special study, and are com- 
paratively modern, in most cases being 
named since the fourth century. 

In addition to the constellations, the 
entire circumference of the sky has 
been divided into twelve parts, which 
have been named the twelve signs of 
the zodiac. This is the apparent path 
of the sun through the heavens. Their 
names and order may be easily com- 
mitted to memory in the following 
rhyme : 

"The Ram, the Bull, the Heavenly Twins, 
And next the Crab the Lion shines, 

The Virgin and the Scales, 
The Scorpion, Archer, and Sea Goat, 
The man that holds the Watering-pot, 

And Fish with glittering tails/' 



Some of these signs of the zodiac 






THE CONSTELLATIONS 101 

are identical with the great constella- / 
tions where they happen to lie in the 
sun's course, notably the Bull, Lion, 
Virgin, and Scorpion; the other eight 
zodiacal signs are simply minor groups, 
made memorable because they are the 
mile-posts of the sun. 

It was explained while describing the 
fixed stars that in reality there are no 
" fixed " stars ; but they move so slowly 
to our eyes that the ancients believed 
them to be stationary. Their proper mo- 
tion, however, causes them to move, and 
therefore the dislocation of the heavens 
is only a question of time. The day will 
come by reason of this motion that the 
neighboring constellations of Orion, the 
Bull, and Canis Major will be merged 
into one immense group. In 5000 years 
this will be our largest and grandest 
galaxy, and will require a new name. 



102 THE PITH OF ASTRONOMY 

Such a period seems long in human his- 
tory, but it is but an hour in recording 
celestial time, when we consider that 
most astronomers agree in placing the 
age of our little modern planet at 20,- 
000,000 years. 

Astronomers can go back in their cal- 
culations w T ith as remarkable accuracy 
as they can predict the future. Fifty 
thousand years ago the Dipper had the 
form of a perfect cross, and in 500 cen- 
turies from now it will assume the shape 
of a steamer chair. 




THE GREAT NEBULA OF ANDROMEDA 

(Visible to the naked eye.) 



NEBULAE 

A nebula is a luminous patch in the 
heavens, billions of miles beyond the 
limits of our solar system. 

There are thousands of nebulas, and 
they are of various composition, color, 
and size. Sir William Herschel observed 
and formed a catalogue numbering 2000 ; 
since his time many have been discov- 
ered by the aid of modern telescopes. 
He estimated that the light from the 
faintest would take 2,000,000 years to 
reach us. 

Most of the nebulas proper are com- 
posed of hydrogen and other gases 
strongly condensed ; this is the nucleus 



104 THE PITH OF ASTRONOMY 

I 

of worlds and planets in the process 
of being condensed into a solid mass. 
There are many worlds in such process 
of evolution known to astronomers, and 
they can be seen in their different stages 
through a telescope. For example, one 
in the constellation of Canes Venatici, 
which shows a central condensation. 
A second is found in Aquarius, and 
shows a sphere in the process of throw- 
ing off a ring ; this ring may in time 
condense and form a satellite. A third 
may be seen in Pegasus, which is sur- 
rounded by rings of gaseous spirals. 
Two of the most celebrated are found 
in the constellations of Andromeda and 
Orion ; both can be seen on a clear night 
by the naked eye, the latter surround- 
ing the middle star of the three stars in 
Orion's belt. This is the celebrated tra- 
pezium nebula — a field of floating, glow- 




THE GREAT NEBULA ABOUT THE MULTIPLE STAR ORIONIS, 
IN THE CONSTELLATION OF ORION 



NEBULA 105 

ing gas, so large that our entire solar 
system would be lost in it. It is one of 
the great startling sights of the sky, 
and those who are privileged to see it 
through a large instrument can never 
forget it. 

In many cases these nebulae are the 
graves of dead worlds and the cradles 
of new ones — immense masses of un- 
organized matter that may have been 
left floating in space — the wreckage 
from collisions of suns, now ready to 
revert back, in the process of time, to 
their original condition, thus sustaining 
the trite saying that nothing is lost in 
nature. 



THE MILKY WAY 

The Galaxy, or Milky Way, is a lumi- 
nous band of irregular form, consisting 
of a great circle entirely surrounding 
the heavens. It contains myriads of 
stars, so crowded together that their 
united light only reaches the unaided 
eye ; this band of stars can be seen on 
any dark, clear night. If we could stand 
where the earth is and have it removed, 
we could see this splendid circle com- 
pletely surrounding us ; it is thus rea- 
soned that we are a part of the Milky 
Way, and that our sun is near the centre 
of it. 

The circumpolar constellations Cas- 




THE CELEBRATED CRAB NEBULA NEAR TAURI 



THE MILKY WAY 107 

siopeia and the Swan are always to be 
found in the Milky Way, while Sirius, 
Capella, and Aquila may be seen on its 
edge when they are in sight. 

The formation of the Milky Way as- 
sumes the general appearance of a sil- 
very ribbon, but in places it is divided 
into two great branches, which after- 
wards reunite. Between these divisions 
are dark places comparatively devoid of 
stars ; one of these, the Coal Sack, has 
become celebrated, and was so named 
by sailors because they could see no 
stars in this dark spot. 

This glorious celestial path has been 
the theme of poets in all ages. Some of 
the best lines written about it are by 
Elizabeth Carter, from which the follow- 
ing is a selection : 

"Throughout the Galaxy's extended line 
Unnumbered orbs in gay confusion shine, 



108 THE PITH OF ASTRONOMY 

Where ev'ry star that gilds the gloom of night 
With the faint trembling of a distant light 
Perhaps illumes some system of its own 
With the strong influence of a radiant sun." 




THE NEBULA IN THE MILKY WAY 



DOUBLE AND MULTIPLE STARS 

Many stars that appear to the naked 
eye as a single object, when examined 
by a telescope or opera-glass are found 
to be composed of two, three, four, or 
even more stars. These are named 
double, triple, quadruple, and multiple 
stars. Some of these are in no way 
connected with each other save by the 
accident of perspective, while in many 
cases they compose a system, and re- 
volve on one another in a fixed period ; 
the periods may vary from a few years 
up to thousands. 

Ten thousand double stars have been 
observed ; the great majority of them 



110 THE PITH OF ASTRONOMY 

are really double ; by the chance of per- 
spective they are sometimes located al- 
most behind each other, although really 
billions of miles apart. 

There are 558 orbital systems known; 
23 ternary systems exist, while 32 
triples are made up of a binary system ; 
and an accidental optical companion, 
Kappa Pegasi, revolves round its part- 
ner in 11 years, which is the shortest 
period known. 

Zeta Aquarii has the longest period 
definitely fixed ; it is 1624 years. 

There are many systems whose peri- 
ods exceed 5000 or 6000 years, but 
enough time has not elapsed since 
first observed to exactly fix their pe- 
riod. 

The most celebrated double stars are 
Sirius and Castor, of the Twins. The 
former has a period of 53 years, and the 



DOUBLE AND MULTIPLE STARS 111 

latter has a companion that revolves 
round it in 1001 years. 

The ternary system of Zeta, in the 
constellation of the Crab, is composed 
of three suns ; the second revolves 
round the first in a period of 59 years, 
and the third round both stars in 600 
years. 

Double stars have almost always dif- 
ferent colors, and frequently exhibit a 
brilliant variety of tints. Beta, of the 
Swan, contains two suns, one being 
golden yellow and the other sapphire. 
Antares and its companion are orange 
and green, respectively. 

Procyon is so perturbed in its motion 
that it is known to have a large dark 
companion, whose attraction affects it, 
but the distance is so immense that no 
observer has yet been able to find the 
mysterious partner, 



112 THE PITH OF ASTKONOMY 

The celebrated star 61 Cygni is a 
telescopic double sun ; the constituent 
parts of it are forty-five times as far 
from each other as the earth is from the 
sun, yet it takes a powerful telescope to 
show any distance between these com- 
panions. No better illustration of the 
vast scale on which celestial mechanics 
are carried on can be found than by re- 
flecting on this proposition. 

These are but the bare, imperfect 
rudiments of astronomy, and represent 
but a taste of what is to come for those 
who wish to pursue this delightful sci- 
ence in its details. The author hopes 
that this little effort will not have been 
made in vain ; it certainly will not if it 
induces some of his readers to take up 
the subject in earnest where he has laid 
down his pen. 



DOUBLE AND MULTIPLE STAKS 113 

" What though no real voice or sound 
Amid their radiant orbs be found ? 
In reason's ear they all rejoice, 
And utter forth a glorious voice ; 
Forever singing as they shine, 
'The hand that made us is divine.'" 



INTERESTING ITEMS 

Nicholas Copernicus. Born at Thorn, 
Prussia, a.d. 1473. To Copernicus must 
be given the first place in astronomy, 
for it was he who, in the face of all 
traditions, founded the Copernican sys- 
tem : placing the sun in the centre, 
with the planets revolving round it. 
Previous to 1543 all astronomers placed 
the earth in the centre of the universe, 
and believed that the stars and planets 
revolved round it. 

Galileo. — Born at Pisa, Italy, 1564. 
He discovered the properties of the pen- 
dulum in 1583, constructed a thermome- 




YERKES TELESCOPE 

(In the possession of the Chicago University. The total weight of this 
instrument is 75 tons.) 



INTERESTING ITEMS 115 

ter in 1597, and invented and construct- 
ed the first telescope in 1609. With 
these appliances he made many impor- 
tant astronomical discoveries. 

His was the greatest opportunity 
given to man in the field of exploration, 
as the new glass placed him where no 
one had stood before ; but the invention 
was his, and he used it to the fullest ex- 
tent. He was imprisoned in Rome for 
accepting the Copernican system. 

Sir Isaac Newton. — Born in England 
in 1642. Newton was the greatest 
mathematical astronomer, and was a 
veritable wizard with figures, distanc- 
ing all men who had lived before him 
or who have appeared since. 

The story of the fall of the apple 
was first told by Voltaire, who obtained 
it from Newton's niece. Laying down 



116 THE PITH OF ASTRONOMY 

the laws of universal gravitation was 
his principal work. 

Newton was a philosopher as well as 
a great astronomer, as the treatment of 
his favorite dog will show. The docu- 
ments completing a great work occu- 
pying forty years were spread on his 
library table ; his dog upset a burning 
lamp and destroyed them. On his re- 
turn to the room Newton affectionately 
patted the dog and exclaimed, " Dia- 
mond, Diamond, thou little knowest the 
damage thou hast done I" 

Sir William Herschel. — Born in 
1738. He discovered the planet Uranus 
and many other celestial bodies. With 
his own hands he constructed the first 
great telescope. It has been said of 
him that in nearly every branch of 
modern physical astronomy he was the 



INTERESTING ITEMS 117 

pioneer. He was the virtual founder of 
sidereal science. As an explorer of the 
heavens he had but one rival — his son. 

Light is that form of luminous energy 
which comes to the eye in succeeding 
waves or vibrations at the rate of four 
hundred and fifty trillions per second. 
It travels at the rate of 186,000 miles 
in a second, and this uniform speed has 
had much to do in settling some of the 
greatest astronomical problems. "With- 
out its aid we would know absolutely 
nothing of astronomy. The division of 
light from the sun by a prism results in 
seven colors, in the following order : vio- 
let, indigo, blue, green, yellow, orange, 
and red. 

This is known as the solar spectrum. 
The most extraordinary phenomenon 
connected w 7 ith light and at present en- 



118 THE PITH OF ASTRONOMY 

tirely unexplained is that every star in 
the sky is a centre of constant undula- 
tions in all directions, which thus per- 
petually cross each other through space 
without being confused or mingled in 
any way* 

The Spectroscope. — This wonderful 
instrument makes known to us the com- 
position of celestial bodies. With a 
system of prisms it divides the light 
from them into lines on a band or rib- 
bon. The order and position of these 
lines denote the chemical composition 
of the body under examination, so that 
we can determine exactly all the sub- 
stances that compose it and their per- 
centages. It is, in fact, the autograph 
of the substance, written with lines in 
colors. The astronomer by its aid can 
as easily tell what the sun or Sirius are 



INTERESTING ITEMS 119 

composed of as a chemist can analyze 
the composition of gunpowder. 

No Light without Dust. — The major- 
ity do not know that the sky is blue 
on account of thousands of millions 
of atoms of dust floating in the atmos- 
phere. Were it not for dust we would 
lack light on earth and the heavens 
would be an inky black. 

Suppose a room absolutely dark save 
a hole through one of the shutters. A 
ray of light will dart through the small 
opening, and one can observe tiny par- 
ticles of dust dancing in that bright 
beam of light. As a matter of fact, it is 
not " the light " we see, but simply a re- 
flection caused by these motes of dust. 

As it is with this shaft of light in the 
darkened room, so it is on a large scale 
throughout the air. The many millions 



120 THE PITH OF ASTRONOMY 

of particles of dust catch the light, re- 
flecting it back and forth from one 
to another, so making the atmosphere 
luminous. 

"Were it not for dust the sky by day 
would appear black, as it does at night 
when there is no moon. The sun would 
appear as an immense glowing ball. 
The moon and the stars would be visi- 
ble throughout the day. Everything 
would appear differently. Where the 
light touched, the eye would be dazzled 
by the brilliancy. The mellow softness 
of the shadows would become an in- 
tense black, and the outlines of objects 
harsh and angular. 

The sunlight, which has been ana- 
lyzed by the spectroscope, consists of all 
the colors of the rainbow, their total 
forming the white light. The white 
light going through a crystal prism is 



INTERESTING ITEMS 121 

broken up into seven component parts, 
the so-called fundamental colors. These 
seven distinct colors of light are the 
result of the different lengths of ether 
waves. Blue is one of the shortest, yel- 
low one of the longest waves. Thus 
the finest dust molecules floating high- 
est in the atmosphere reflect only the 
blue light, imparting that tint to the 
heavens. 

Tycho Brahe % the celebrated Danish 
astronomer, was born in 1546. Fred- 
erick II., of Denmark, noticing his re- 
markable talents, built an observatory 
for him on the island of Huen, and here 
it was, without the aid of a telescope 
and with the crudest instruments, he 
made observations that afterwards in 
the hands of Newton and Kepler were 
destined to settle the great problems of 



122 THE PITH OF ASTRONOMY 

astronomy. It is asserted that he has 
never been surpassed as a practical as- 
tronomer, although he rejected the Co- 
pernican theory. He was eccentric in 
his conduct, and never made an obser- 
vation in his observatory without put- 
ting on his court dress, alleging that 
if men dressed in honor of the king and 
court they should not be less observant 
of such duties in the presence of their 
Maker. 



THE END 



POPULAR ASTRONOMY 

By Simon Newcomb, LL.D., Superintendent 
American Nautical Almanac ; formerly Profes- 
sor U. S. Naval Observatory. With One Hun- 
dred and Twelve Engravings, and Five Maps 
of the Stars. 8vo, Cloth, $2 50 ; School Edi- 
tion, 12mo, Cloth, $1 30. 

Its purpose is to enlighten that great mass of fairly edu- 
cated people who have lost the astronomical knowledge 
that they once possessed. It states the latest methods of 
investigation, the latest discoveries, and the latest general 
development of this majestic and almost infinite science. 
Great thought and much space have been given to the his- 
torical points and philosophical aspects of the science. . . . 
In the treatment of weighty and abstruse scientific subjects, 
he never fails to bring them within the range of the average 
popular comprehension. — Boston Post. 

The great reputation which the author of this work has 
merited and enjoys, both in this country and in Europe, is 
a sufficient guarantee of its excellence. ... He has dwelt 
especially upon those topics which have just now a popular 
and philosophic interest, carefully employing such language 
and such simple explanations as will be intelligible without 
laborious study. Technical terms have as much as possible 
been avoided. Such as were employed of necessity, and 
many that occur elsewhere, have been fully explained in a 
copious glossary at the end of the book. With its abundant 
aid the reader cannot fail to derive both pleasure and en- 
tertainment from the study of what is the most ancient as 
well as the most elevating and inspiring of all the natural 
sciences. . . . Professor Newcomb, throughout his whole 
volume, preserves his well-known character as a writer who, 
in treating of scientific subjects, fully understands the art of 
bringing them within the range of popular comprehension. 
.... It is fully calculated to hold the attention of the gen- 
eral reader.— N. Y. Times. 



Published by HARPER & BROTHERS, New Yore 

J8®=" The above work is for sale by all booksellers, or will be 
sent by the publishers, postage prepaid, on receipt of the price. 



RECREATIONS IN ASTRONOMY 

With Directions for Practical Experiments and 
Telescopic Work. By H. W. Warren, D.D. 
With Eighty -three Illustrations and Colored 
Plates. 12mo, Cloth, $1 25. 

Written not only to reveal some of the highest achieve- 
ments of the human mind, but also to let the heavens de- 
clare the glory of God. With sentiments of profound devo- 
tion, and with the calmest belief that religion gains by 
every advance of science, he invites the reader to scan the 
heavens, and there find proofs strong as holy writ of the 
truths of revealed faith. Dr. Warren writes like a scholar— 
clearly, tersely, elegantly.— Chicago Times, 

The style of the author is flowing and easy, so that even 
his most scientific pages will make the reader pause and 
catch the drift of the writing. The book will more gener- 
ally interest readers that most books upon scientific sub- 
jects. It has an enthusiasm which is contagious. The 
author has mastered well the art of bringing science into 
the range of the common reader and making it both pleas- 
ant and profitable.— Chicago Inter-Ocean. 

The explanations of difficult matters are particularly lucid, 
and for readers not technically instructed in astronomy 
nothing could be better as a literary presentation of the at- 
tractive side of the science.— N. Y. Evening Post 

A very attractive book . . . treating the subject in so fa- 
miliar a manner as to make the practical and useful informa- 
tion it contains delightful reading.— Boston Commonwealth. 



Published by HARPER & BROTHERS, New York 

$W The above work is for sale by all booksellers, or will be 
sent by the publishers , postage prepaid, on receipt of the price. 



